Slip sheet control



Ap 9, 1940. F. NIGRA SLIP SHEET CONTROL INVENTOR.

I FERDINAND NIGRA BY ATTORNEY Filed Jan 30, 1939 Patented Apr. 9

UNITED STATES I 2,196,506 SLIP SHEET CONTROL Ferdinand Nigra, SanFrancisco, Calif., assignor t Niagara" Duplicator (30., San Francisco,

Calif.

Application" January 30, 1939, Serial No. 253,495

7' Claims. (01. 34-1) The invention relates to a slip-sheeting devicefor use at a receiving tray for printed sheets discharged from'aprinting apparatus, and' more particularly concerns'a control for thedischarge of the slip sheets from -a supply stackthereof and intointerleavingiposition between the printed sheets in the tray.

An object of the invention is to provide a device for automatically andpositively initiating themovenient ofa released slip sheet which wouldotherwise descend to its operative position The invention possessesother objects, and" fea- 20' turesof advantage, some of which, with theforefollowing description of a typical embodiment of the invention, andin the accompanying draw ing in which,

Figure -1 'is a perspective view of a slip-sheeting 25 unit having thecontrol device of the present inventionprovided in operative associationtherewith. r Figures 2 and 3 are fragmentary transverse 3 sectionsthrough a slip sheet supply tray of the elevation and operativeagainststacks of slip sheets respectivelyihaving many and few sheetstherein. Figure 4 is a transverse section through the slip sheet supplytray and showing the pressure device inoperatively disposed with respectto a stack of slip sheets in the'tray.

Figure 5 is an enlarged and fragmentary section through'the pressuredevice.

The features of the present invention are'generallyapplicab le inconnection with a slip-sheeting unit 1 for use with a printing mechanismsuch as a printing press or a duplicator which discharges printed sheetsfor gravity deposit in a tray underlying the unit, with the sheetsmoving laterally as they settle into place in the tray.

In the presentinstance; printed sheets delivered from between thestencil and the impression roller of a duplicatorsuch as that disclosedin my United States Patent No. 2,139,132 which issued onzDecember 6,l938,*are arranged to fall into a collecting tray 8 of the unit from anend thereof, and means are provided for interposing separator, or slip,sheets 9 between the printed sheets as the latter are, delivered to thetray.

going, will be set forth or be apparent in the unit, and disclose apressure-producing devicein Ags'particularly illustrated, a stack of theslip sheets '9 is arranged for support in a frame or tray I I mounted onand above the tray 8 in unitary association therewith and having an openbottom, and means are provided for releasing the sheets 9 one at a timefor-falling upon a delivered printed sheet in the tray 'll before thenext printed sheet is delivered, the device being known in the art asslip-sheeting. 1

The slip sheets 9 are alike and are each provided' with'two spacednotches l 2 in each side edge thereof, the notches of the two sheetedges being equally spaced apartbut difierently spaced with respect tothe same sheet end. In a stack of the slipusheets for use in the presentunit, alternate sheets are reversed as to the disposal of the sheetnotches l2 in the stack, whereby the correspondingly disposed notches ofthe sheets define four lines thereof ateach stack edge defined bytheside edges of the sheets. In the present slip-sheeting unit, thestack of sheets in the tray l l is supported on four rollers I3 whichengage in pairs beneath the opposite stack sides andmay pass through thenotches I2 when they register therewith. In plan arrangement,

the support rollers l3 are spaced exactly as the notches I2 of a slipsheet 9 and are arranged for their simultaneous disposal beneath thebottom sheet of the stack at its notches [2 whereby they may engage thenext highersheet through the notches of the bottom sheet to therebyrelease the latter and assume the support of the stack through the newbottom sheet.

The rollers l3 are mounted on the inner ends of stub shafts M whichextend beneath thestack from bars l5 disposed and supported atoppositesides of the tray l l asthe primary support means for the stack;in this manner, areleased slip sheet 9 may fall freely into theunderlying tray 8. In the drawing, the rollers l3 are shown as beingdisposed to supportedly engage the lower sheet of the stack. Theroller-carry ing bars l5 are mounted for their longitudinalreciprocation in their planes and are pivotally connected by a cross-bar16 which is pivoted centrally of its connections with the bars I5 to arearward projection ll of the tray H, the

arrangement being such that a rocking of the cross-bar l6 horizontallyand about its pivot point is arranged to'oppositely shift the bars l5and their rollers Hi to like degrees.

Following the release of the bottom sheet of astack of slip sheets 9 byreason of the registration of the set of rollers l3 with its notches [2,

an opposite shifting of the barsl5 to dispose the rollers beneath thenotches of the new bottom sheet will release this sheet, it thus beingunderstood that the slip sheets 9 may be released from the bottom of thestack and one at atime by oscillating the control bar It betweenlimiting positions thereof which disposed the rollers 13 insheet-releasing positions. My aforesaid United States Patent No.2,139,132 discloses in detail one suitable means for effecting theoscillations of the bar IS in synchronism with the delivery of printedsheets from a duplicator whereby the desired insertion of slip sheetsbetween successive printed sheets may be effected as the printed sheetsare deposited in. the tray 8.

Since the slip sheets 9 are used repeatedly and are disposed inalternate arrangement in a stack thereof, means are preferably providedfor retaining the sheets in theirrequired order and arrangement, saidmeans also providing a stop to limit the movement of the printed sheetsin the tray 8. As is particularly illustrated in Figure 1, aU-shapedmenrber I8 is provided for the insertion of its legs 19 throughspaced openings 20 provided in the sheets 9,said pair of openingsdefining a line transverse to the longitudinal axis of the sheets, andcorresponding openings being aligned in the stack whereby the legs l9may be disposed therethrough. 'The lower extremities of the legs iii arearranged to engage in'openings 2| of the bottom plate 22 of the tray 8whereby the member ll may be disposed and held in a plane perpendicularto that of the tray bottom to extend upwardly through the slip sheetstack in which it engages. It will be understood that the legs l9 of themember i8 operate as a stop means to limit the lateral delivery movementof the printed sheets in the tray 8 for insuring their orderly disposalbetween adjacent slip sheets 9 as the printed sheets and slip sheets arealternately deposited in the tray.

It will now be noted that the slip sheets 9 comprise thin and fiatpieces of cardboard or other suitable material, with or withoutink-blotting faces, and are inherently still enough to tend to retain aflat condition thereof when individually free, whereby they may havetheir normal flat form while falling into operative position and may beassembled for providing a compact stack having the present arrangement.The slip sheets are transversely flexible while resiliently resistingbending, and a stack of such sheets supported only along its oppositesides, as by the rollers l3, has successive sheets thereof mutuallyengaged in relatively close face-to-face relation. When the bottom slipsheet 9 of a stack is released for its falling upon a printed sheetwhich is being delivered beneath it, air must penerate between thereleased sheet and the overlying sheet of the stack before the releasedslip sheet may begin falling freely to its appointed place, and it hasbeen found in practice that such air penetration may be so slow when theengaged sheets of the stack are substantially flat as to seriously limitthe permittedrate of operation of the printing mechanism by reason ofthe limitation imposed by the retarded and variable rate and directionof delivery of the slip sheets from their stack.

' Experiment has shown that the foregoing air binding of the slip sheetsmay be largely overcome by flexing the supply stack of slip' sheetsdownwardly between the lines of support provided by the rollers 13 atits side edges, as is illustrated in Figures 2 and 3. When the stack ofslip sheets is so flexed, the side edges of a released bottom sheet willpositively pull away from the secured the discharge and positioning ofslip sheets is necessary for a most rapid and efiicient operation of aprinting mechanism which supplies printed sheets for interleaving, meansare provided for ,slip sheets in the tray II to positively'andconstantly flex the'stack'to a desired degreewhich is determined by theresiliency of the sheets.

The assembly 24- essentially comprises a thrust member 25 arranged forits application transversely against the top slipv sheet in the tray IImore or less centrally thereof, a support element 26 mounted across thetray above the stacked sheets therein and carrying the member '25 forits guided and axial reciprocation, and a compression spring 27constantly 'coactive between the element 26 and the member 25 toresiliently urge a down thrust of the member against a stack of slipsheets in the tray when the member 26 is fixed in place on the tray.- Inthe present. in-

stance, the member 26 comprises a fiat and trans.- versely rigid bar forspanning the tray and attached to a tray side 28 by means of a suitablehinge 3!. A spring catch 32 is mounted at the outerface of theoppositetray side element 29 for receiving and securing the free end of the barin position adjacentand opposite the top lip of the side 2-3 whereby thebar may be releasably secured across the top of the tray.

Inthe present structure, the member 25 comprises a cylindrical rod andthe bar .26 is centrally perforated to receive the rod Ziperpendicularlytherethrough. A sleeve member 33 slidably receives the rod 25 and hasone end fixed in the bar opening, said sleeve providing a guideway forthe rod. A ring or flange 34 is provided on the rod 25 adjacent itssheet-engaging end and provides a spring seat between which and theopposed end of the sleeve 33 the spring 21 is constantly operative tourge the rod axially toward a limiting position which is determined by asuitablestop means. As shown, a pin '35 is mounted in thesleeve 33 toengage .a slot. 36 extending in a side of the rod longitudinallythereof, the slot end 36' furthest from the ring 34 engaging the pin tolimit the operative extension of the rod when all slip sheets haveescapedfrom the tray H or the assembly 24 is inoperativelydisposed. Itwill be understood that the extension of the pin 35 into the slot 36also prevents a rotation of the rod 25 in its mounting.

The thrust rod end which is to engage theslip sheets is forked to mountacylindrical wheel or roller 37 which is arranged to provide anantifriction contact end for the rod andis mounted whereby to facilitatethe swinging down of the member from the position shown in'Figure 4 toforcibly and resilientlyengagethe' rod with a stack of sheets on thetray through the roller 38 as in Figure '2'; it beingflunderstood thatthe stop pin 35 functions to maintain the aforesaid positioning of theroller-"for its rollin engagement facrossthe top slip sheet as themember 26 is swung to and from its locked-down position.

The ,roller 38 of the operative rod 25 preferably engages the top slipsheet at or adjacent its'longi- I tudinal center'line, and centrally ofthe sheet ends, and is arranged to constantly flex the stack of sheetsdownwardly along the longitudinal center line of the stack and betweenthe pairs of support rollers l3 beneath the opposite stack sides, as isshown in Figures 2 and 3. The strength of the helical compression spring21 is such that the desired maximum degree of bowing is produced in afull stack of slip sheets when the rod 25 is operative, and the samedegree of bowing is maintained as the sheets are dropped and the springis allowed to correspondingly. expand. The latter important relation ismade possible by the fact that the resistance to the .released therefromand the stack becomes thinner. v

With the positively operating sheet-flexing device now disclosed, thesheet-freeing action as a sheet is released will be so closelyconstant-for all sheets of the stack that the maximum possible rate ofdelivery of slip sheets from a supply stack on the rollers 13 may bepredetermined and maintained while using the slip-sheeting unit inassociation with a printing mechanism which may deliver printed sheetsat said predetermined rate. Since the possible rate of delivery of theslip sheets with the present control device isconstant and isappreciably greater than with a solely gravity delivery, the presentdevice permits a much higher printing rate than would otherwise bepossible. It will, of course, be understood that the weight of thethrust rod assembly which is constantly added to the'push of the rod 25comprises a minor, if not negligible, part of the flexing force againstthe slip sheets of a stack in the supply tray. It will also beunderstood that the present .device is applicable to'the interleaving ofother than printed sheets. From the foregoing description, taken inconnection with the accompanying drawing, the advantages of the presentinvention will be readily'under'stood by those skilled in the art towhich the invention appertains. While I have described the princislipsheets between successively delivered sheets for separation, meanssupporting a supply stack of the slip sheets in generally horizontaldisposition and engaging the stack solely beneath opposite side edgeportionsthereof, means for actuation torelease the bottom slip sheet ofthe stack for its operative disposition by falling, and means engagingthe top of the stack centrally thereof to constantly flex the samedownwardly to a fixed and predetermined degree whereby, the releaseofthebottom sheet will permit a flattening out of the released slip sheetto positively free it from the immediately overlying sheet.

2. A structure accordance with. claim 1 wherein the last means comprisesa springpressed member which is operative transversely against the topof the stack.

3. In combination with a tray for horizontally receiving a succession ofprinted sheets from a printing mechanism, a device for. interleaving thesuccessive sheets during the deposit thereof comprising a structuresupportedly engaging an or-v derly stack of resiliently flexible andinherently flat slip sheets solely beneath opposite side edges of thestack and in'horizontal disposition above said tray and for the releaseof the successive bottomsheets of the stack to fall therefrom intointerleaving position, and a pressure member constantly and resilientlyreactive between said supporting structure and the top of the stackintermediate of its supported edges to flex the stack downwardly. q

4. In a device for interleaving successive sheets during the gravity andlike depositv thereof in a stack, a structure'supportedly engaginganorderly stack of resiliently flexible slip sheets above the point ofdeposit of the first sheets and solely at opposite sideedges of the lastsheets for the release and free falling of the successive bottom slipsheets of the stackinto interleaving relation with the first sheets,side elements of said structure'beyond opposite sides of the stack, arigid cross-member relea'sably connected to and be-, tween said sideelements and spanning the stack,- a thrust memberextending transverselyfrom the cross-member and engaging the top of the stack transversely andcentrally thereof, and a compression spring constantly reactive betweenthe cross-member and thrust member to forcibly engage the latter memberwith the stack to bow the stack downwardly between its supported sides.

5 In a device for inserting slip sheets between successiveprinted'sheets during the gravity deposit of the latter in a stack thereof,astructure supportedly engaging an orderly stack of resiliently flexibleand inherently flat-slip sheets above the point of deposit of theprinted sheets and solely at opposite side edges of the stack for therelease and free fall ofv the successive bottom slip sheets of thestackthereof into interleaving relation with the printedsheets, fixedside elements of said structure at opposite sides of the stack, atransversely rigid cross-member hinged to a side element for swinging toand from a spanning disposal thereof over the stack, a catch on theother side element for releasably engaging the free end of thecross-member to secure said member in stack-spanning position in thestructure, a thrust member carried by the cross-member and extendingtransversely thereof toward the stack and provided with an anti-frictionmeans at its free end for engaging the top of the slip sheet stackcentrally thereof when the the cross-member and thrust member'toforcibly I engage the anti-friction means of the latter with thestack to bow the stack'downwardly between its supported side edges. t 6.Alstructure in accordance with ,claim 5 whereinthe anti-friction meanscomprises a rolier arranged for its rotation in the plane of swinging ofthe cross-member. 7

7.111 a device for inserting resiliently flexible slip sheets betweensuccessively delivered sheets for separation, means supportedly engaginga 10 stack of the slip-sheets solely at difierent side

